Reversible internal-combustion engine



L. S. STEVENS, DECD. c. snvaus. ADMlNlSTRATRIX. REVERSIBLE INTERNAL COMBUSTION ENGINE.

APPLICATION FILED JUNE 9, 1915.

1 ,331,399. Patented Feb. 17, 1920.

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$1 /Z KM L. S. STEVENS. DEC'D.

C. STEVENS, ADMINISTRATRIX. REVERSIBLE INTERNAL COMBUSTION ENGINE.

I I APPLICATION FILED JUNE 9.19I5. 1,331,399. Patented Feb. 17,1920.

3 SHEETS-SHEEI 2.

L. .S. STEVENS. DEC'D. c. STEVENS. ADMINIST-RATRIX. REVERSIBLE INTERNAL COMBUSTION ENGINE. APPLICATION FILED swam-191s.

1 ,33 1,399. Patented Feb. 17,1920.

3 SHEETSSHEET 3.

WWM/JLZW UNITED STATES PATENT OFFICE.

LYMAN S. STEVENS, 0F BALEEMOEt-E, IQIJi-EEYLAND; GGRA STEVEN-S ADMINISTRATRIX 01 I SAID LYMAN S. STEVENS, DECEASED.

REVERSIBLE INTERNALGOI1IB'USTION ENGINE.

Specification of Letters Patent.

Patented Feb. 17, 1920.

Application filed June 9, 1915. Serial No. 33,112.

To all whom it may concern:

Be it known that I, LYMAN S. STEVENS, a citizen of the United States, residing at Baltimore, State of Maryland, have invented certain new and useful improvements in Reversible internal-Combustion Engines, of which the following is a specification.

This invention relates to internal combustionengines used for converting the latent thermal energy of hydrocarbon, oX -carbon, gaseous evaporates, and other combustible gases into dynamic energy for power purposes.

An object of my invention is to provide means for making an internal combustion engine as readily and certainly reversible as is the reciprocating steam engine.

Another object is' to provide means for scavenging fully the exhaust charge in the cylinder, and thoroughly ejecting all, or

practically all, of the burned products of combustion, so that the incoming charge will be capable of being ignited at a low temperature and compression, due to the fact that there are none of the carbon dioXid gases left to contaminate the new charge of fuel and air.

Further objects are to provide means for proportioning the fuel to the air in a manner that is absolutely under the control of the operator; to provide a mixture of fuel and air that may 3 ignited at any partof the piston stroke with certainty; and to provide means for starting the engine with the pressure of the fuel or other gas in. either direction as desired.

These objects are attained in the manner and by the means hereinafter described and claimed, reference being had to the accompanying drawings, in which Figure 1 is a side elevation, partly in sec tion, of an internal combustion engine embodving my improvements.

Fig. 2 is an enlarged detail side elevation,

partly in section, ofthe valve and firing device reversing gear.

Fig. 3 is an enlarged detail view of the valve gear starting device.

' Fig.4 is a detail sectional view taken on the line IVTV, Fig. 3.

Fig. 5 is an enlarged. detail sectional view of the engine piston with its cooling system applied.

Similar numerals of reference denote corresponding parts in the several views.

-as described in said application.

Referring to Fig. 1, the valves 2 are connected to a reservoir of gas under a pressure suicient to actuate the engine part of a. revolution, or until the engine has taken in a charge of at the other end of the Piston S, which will occur at a one-half revolution of the crank shaft 1. This gas may be of any character, such as air under pressure, though preferably I employ the fuel gas used with the en ine, as the same is present under suflicient pressure, as hereinafter will be described. The valves 2 are then closed and the engine is in condition to operate at the will of the operator without other means than the impulse from the explosions of internal fuel charges.

The engine is shown as being at the top of the stroke, and at the moment of receiving an impulse from the firing of the charge at hat end, and the sequence of events will be as follows:The engine crank rotating to theright will at the position shown exhaust the products of the burned charge below the piston 8, and be receiving a scavenging charge of air from the air pump receiver 5 thi valve 6. and this cleaning charge will be injected at a pressure of about four pounds per square inch, and as the capacity of the air pump cylinder is about fifty per cent. greater than the cubic contents of the cylinder 7, the burned products of the last charge effectually will be cleaned out, and none of the objectionable carbon dioxid will remain in the cylinder to contaminate the incoming charge.

As the piston 8 passes the opening to valve 6 on the down stroke, the lower valve 1 will open and admit a portion of gas or vapor into the-cylinder below piston 8 at a pressure of about twenty pounds, which gas cannot, escape into the exhaust as all ports of egress are closed. In an application for I; tters Patent filed by me May 25, 1915, Serial No, 30,310, for improvements in apparatus for measuring the charge of fuel and air in'internal combustion en ines, I have disclosed an improved means or supplying a measured charge under pressure to the worki cylinder or cylinders of such an engine, which mechanism is embodied in the present invention, as follows: The gas or vapor admitted through valve 3 into the pipe 3, is measured by means of the adjustable piston 3 in the measuring cylinder 10,

This

charge thus will be discharged into thecylinder 7 .bBlOWzpiStOIl 8 until the pressure in said cylinder 7 and in the measuring cylinder 10 and pipe 3 are equalized, at which time the cam 11 will closethevalve 1 and the pressure will be completed by the fur ther downward movement of the piston.

On the Lip-stroke, this cycle of operations will be repeated.

Theair pump 12 is attached to the main engine by means of beam 13 and connecting rods14 and 15, and its function is to supply a charge of pureair into the cylinder 8 at each] endof the stroke, and at the same operation to clear the cylinder of the products' of combustion of 'the last charge of gas and air. A small proportion of carbon dioxid 'has a most potent effect in raising. the "temperature at which the fuel charge" will'ignite, and as this heat must be supplied by the heat of compression, it is evidentthat the compression will have to be carried to a high point to make certain the explosion of the chargeywhich is the reason forthe uncertainty of the combustion in the usual engine. For this reason the air pump should be. about fifty per cent. greater in cylinder capacity than the engine cylinder. The air will be delivered at about four pounds per square inch pressure to the cyl inder 7, and the piston 8 having vuncov ered the exhaust opening 9 just before the uncovering of the air admission port 6, the

pressure in cylinder 7 will be at less than one pound when the air charge isadmitted to said cylinder. V

The operation andfunctions of the cam 11 are as followsbUpon the rotation of the crank on shaft tto the right frointhe position shown in Fig. 1, an eccentric 17 is operated through the gears 18, 19v and 2O, from shaft 4. ,c This eccentric 17 operates rod 16, whichin turnoscillates the cam 11 and causes the projection 21 thereonto actuate the valve stem 22 and open the valve 3, thereby admitting a charge of compressed gas from a supply cylinder (not'shown) to the cylinder 10 and its supply pipes 3 The further movement of the cam 11 causes the projection'2 l thereon to engage the lower end of shaft 23, thereby opening the upper valve 1 to permit a discharge of compressed chargefrom pipef3 into the upper end of cylinder 7 Upon'the return movement of rod" 16, due to the further rotation of the ca mf17, the projection 21 again opens valve 3 to admit a fresh charge to the cylinder l0 andpip'e 3", and as the rod 16 approaches its lowermost limit of movement the 'projec tio'n'2f1 on cam'll' will contact with the upper; end of rod 23*, thereby opening the lower valvel to admit the charge from cylinderf 10 and'pipe 3 into the lower end of cylinder 7.

the position of the and this will cause the valve gear'and the pipe 3 may be changed readily byaltering I 7 piston manually through screwrod 26 and wheel 27 ,as the rmovementof said pistons? outward will increase the charge,; which will cause a higher compressionin the cylinder 7 and increase the speedof the engine. This engine speed may be varied as muchas seventy per cent. by the piston 3, and the proportions altered from about twenty to one to four to one in the cylinders, according'to the quality of gas'an'd the'desired speed of the engine.

I also find that it'is advisable to enrich the 'fuel charge-at. the time of starting the engine, as it will be necessary'to secure an impulse at a low compressioinanda greater impulse will be required at that time. I accomplish this by moving the piston 3" out wardly to increase the initial supplyof gas in cylinder 10 andpipe 3 and when the l engine has started said piston 3 maybe again changed to suit the desired speed'of' the engine. l

Referring to Fig; 2, which represents the valve "and firing device reversing gear, thegear 18 is providedwith'a long boss sleeve 28in which is an interior helical groove or set of grooves, in which fit the helical splines of a sliding sleeve 29, which may be adjusted by the collar 29*, and in its motion is caused to rotate part of a revolution in one direction, and this'helical splined sleeve 29 has a set of'interio r grooves also helical that engage helical splines '30 on shaft 31 and these being of'the'opposite direction'to the splines on the sleeve 28 will cause. a still further motion of the shaft 31 on-which eccentric 17 is secured, 'and'by which, through rod. 16, motion to cam 11 is transmitted; The pitch of these 'splinesare so related that the full throw of the shaft31 is secured for a forward or backward motion of the engine by passing the'slee've' 28 from one extreme end position to the other extreme,

firing devices to assume their properpost tions in regard to the crank shaft 1. i 'Fig. 3 represents the-valve gear starting device, to be used in casetherois no charge of combustible gases in the cylinder, and in which 32' is a cam that is actuated by a-rod admit thehigh pressure gas to thefcylinder 7 and actuate the piston 8 as the pressure may be admitted to either end of the cylin-- der '7 asthe exigencies may demand, as will be understood?" As thecani s2-' ressesagainst either of the blocks 35 it raises its valve stem 88 and actuates its valve 2 in the following manner: Each block 35 normally is in contact with a toe 36 fixed to the end of eacherod 38, and when actuated by cam 32 moves said toe and with it its rod 38 to open its valve 2. Said blocks 85 are slidable vertically on a common rod 40, and have a tongue and groove connection with their toes 36, as shown in detail in Fig. l. Saidrod 40 is movable toward and from the cam 32 by means of link 42 and arm 43 on shaft let and at its ends is carried in blocks n slidably mounted, in suitable fixed guides 37.

lVhen it is desired to start the engine, the

operation. is first to place the splined sliding sleeve of said eccentric 3% in position for the proper desired direction of rotation, and then force the rod lO and sliding blocks 41 inward by means of the link 42 and arm i3 on shaft 4A, to the position shown in Fig. 3, when the cam will engage the proper toe and admit the pressure gas to the proper end of the cylinder 7 for the desired impulse.

Fig. 5, which represents the piston and crosshead trunnion with the water cooling system for the piston ends, shows in section the piston with the cross head trunnion passing through the same, and shows the water cooling pipes in elevation. The coo1- ing water firstis introduced through pipe which is held stationary, while pipe t8, which telescopes therein, is fastened. securely to the trunnion end of piston 9. As the piston travels from end to end of its stroke the pipes 48 and a9 travel through their respective packing boxes 4:7, the water passing through pipe 45 to pipe 48 and then through the trunnion and pipe 50 to the chamber in piston end 51, and through this to pipe 52 and then to piston end 53 and up through pipe 5% to the other end of trunnion 55 and then through the pipes i9 and 46. This circulation effectu ally will cool the piston ends 51 and 53 and prevent any premature explosion due to the gradualheating of the piston ends to a red heat due to constant operation. Suitable check valves 56 and 57 in the pipes 58 and 59, leading intopipes 45 and 46 are necessary in pumping the water of the circulation through the pistons and cylinder cooling chambers, and the stroke and di ameter of the pipes 48 and d9 control the amount of water that is used as a cooling medium for each cylinder.

This cooling water first cools the pistons and then is circulated through the cylinder water cooling chambers and as the water maintains the piston heads at a low temperature the ignition of the compressed charge is by this cause eliminated.

Ininy engine I use an exterior air pump for purposes of scavenging, as I find that it is impossible efi'ectively to expel all of the burned gases of an internal combustion engine unless the scavenging charge is sufli ciently great to ii ll the cylinder completely, and above this amount, approximately fifty per cent. more air should he passed through the cylinder to eliminate the carbonic acid gas of combustion. The ordinary two and four cycle engines rely upon a volume of air equal to or less than the displacement of the piston in its stroke, which is about eighty per cent. of the contents of the cylinder, and when the piston is going through the scavenging process at the exhaust pe riod, there is about twenty per cent. or more, of the old charge remaining in the cylinder at the beginning of the next compression stroke, and this twenty per cent, in the well known manner, prevents combustion except ata high temperature, consequently they will fire at high compression only, and this with no certainty. But in my en gine, 1 use a volume of about fifty per cent. in excess of the cubic contents of the ex plosive chamber when the piston is beginning the compression stroke. 7

When the explosive impulse is in effect, the piston of my engine moves toward the exhaust end of the stroke, and previous to the full stroke consummation the exhaust port is opened, as is common in two cycle engines, and the actuating charge of burned gases has reduced to about two pounds, gage pressure when the air inlet port is opened by the movement of the piston. The air of the scavenging charge then is admitted at practically a constant pressure of about three pounds at the exhaust end of the cylinder, said air being admitted against curved baffle projections on the piston head and diverted toward the cylinder head of the engine on that end. A volume of about fifty per cent. in excess of the cubic con tents will be admitted to the combustion chamber, and practically all of the burned products and one-third of the air injected will pass from the cylinder. As soon as the piston closes the air admission port and the exhaust port, there is admitted to the cylinder the measured amount of fuel from the measuring apparatus under compression which will be all entrapped. as all ports of egress are then closed, and this fuel will at once expand until the pressures are equal iZed, and then the fuel admission port is mechanically closed and the piston in its motion completes the period of compression, and the mixture of the fuel and air is ignited in any usual manner. But I prefer a multiple electric ignition with about four igniters to each cylinder of twenty four inch diameter or over, which are not shown in the drawings.

In operating the engine, and beginning at in Fig'.'l,'-1 provide the valve 2 on each end of the cylinder 7 for the admission of a" compressed iexpaiisiblo gas,- in this instance at the upper end of the cylinder- 7, which will force the piston 8 to the bottom and 5 give the crank shaft about one half of a rotation and thus fill the other end of the cylinder with an expansible charge of air and fuel, through lower valve 1, in a mannerhereinbefore described; and as this will at the proper position explode the engine will be in operation, and at the moment of the first explosion, the high pressure gas admission valves will be closed by the operator, and the engine then will operate under the cycles of explosive operation. As

7 the high pressurevalves are under control 20 so as-t'o admit the gas into the cylinder at a pressure at either end of the-cylinder as desired to suit the exigencies of rotation, the engine will start in either direction and continue so lon as the fuel is supplied and the firingdevice is connected. 7

To reverse the engine when in motion I disconnect the firing device and allow the engine to come to a full or near full stop,

and then reverse the explosive firing device.

' "This will cause the firing or explosive impulse to be so timed as to cause an explo sion at the proper time to actuate the env giiie in the opposite direction with certainty, as there will be no contaminating gases to cause a nisfire of the charge of air and fuel. In the construction of the long piston of the engine, I provide means for cooling the piston ends with a circulation of water, and

each piston pumps the circulating water for its own cylinder cooling, by means of a combination of tubes with suitable check valves in them to form suction and delivery sides automatically as the piston is propelled from end to end of the stroke, as hereinbeforedescribed. These tubes are connected to the ends of the cross head trunnions, and

in this manner the cooling Water of each cylinder is independent of the other, and if one is nonoperative the others will not be aifected. 7

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is

1. In an internal combustion engine, means controlled by the engine shaft for s'uo l in a measured combustible char e under pressure to the engine, means for varying the measure of said charge manually, means controlled by the engine shaft for admitting the charge to the cylinder, and means for reversing the engine by changing the time of admission of the charge. 7

2. In an internal combustion engine,

nieanswontrolled by the engine shaftfor under p'ressure to the engine, means 'i for varying thenieasure of said charge nianu-' ally, means controlled 'by the engineshaft for admitting the charge to the cylinder; and means for reversing-the engine by changing the time of admission of thec'harge, said reversing means being disposed intermediate the engine shaft and the charge admission valve. 7

3. an internal combustion engine, means controlled-by the engine shaft for supplying a measuredcombustible charge under pressure to the engine, means for varying the measure of said charge manu ally, means controlled'by the engine shaft for admitting the charge to the cylinder, and means for reversing the engine by changing the time of admission of the charge, said means comprising an admission valve, an eccentric controlling the movement of said valve and operated from the engine shaft, and mechanism for shifting the position of said eccentric relative to said engine shaft. I

4:. In an internal combustion engine, means controlled by the engine shaft for supplying a measured combustible charge under pressure to the engine, means for ed to shift the position of said eccentric at will. i c 7 5.111%111 internal combustion engine,

means controlled by the engine shaft for supplying a measured combustible charge 7 under pressure to the engine, means for varying the nieasure of said charge manually, means controlled by vthe engine shaft for admitting the charge to the cylinder, and means for reversing the engine by changing the time 'of' admission of the charge, said means comprisingan admission valve, an eccentric controlling the movement of said valve and operated from the engine shaft, and mechanism for shifting the position of said eccentric relative to said engine shaft, said shifting mechanism comprising a longitudinally movable sleeve. splined exteriorly and interiorly with opposite pitchesand engaging corresponding grooves in coacting elements, one geared to the engine shaft and the other carrying said eccentric.

' 5.111 an internal -wmbiistion; engine, a

piston, means for supplying a combustible charge to either end thereof under pressure sufficient to cause a movement of said piston due to said pressure, and manually operated means for first admitting said charge to either end of said piston at Will.

7. In an internal combustion engine, a source or fuel supply under pressure, an engine cylinder, a double ended piston therein, valves at each end of said cylinder for controlling the admission of said gas under pressure to said cylinder ends, valve rods therefor, an eccentric for operating either of said valve rods to open its valve, shiftable means connected with the engine drive shaft for timing said eccentric, and means intermediate said eccentric and rods manually shiftable to disconnect said eccentric and rods.

In testimony whereof I afiix my signature.

LYMAN S. STEVENS. 

